Legalizing same-sex marriage in Illinois could give Democrats a much-needed boost of enthusiasm headed into next year’s critical elections, though financial woes and high unemployment could mute long-standing traction for the party that rules the state.

For Republicans, the gay marriage vote could put a renewed focus on social issues for a GOP that had hoped to keep its arguments against Democrats next year based on fiscal concerns.

Such is the potential political fallout from the General Assembly’s narrow vote Tuesday to make Illinois the 15th state to approve a measure allowing same-sex couples to wed. On Wednesday, Democratic Gov. Pat Quinn said he would sign the bill by month’s end.

Among the four major Republican challengers to Quinn, state Sens. Bill Brady of Bloomington and Kirk Dillard of Hinsdale voted against the marriage bill. Another contender, state Treasurer Dan Rutherford of Chenoa, voted for civil unions as a state senator but opposed same-sex marriage.

Lawmakers provided a pass to GOP governor contender Bruce Rauner, who repeatedly has refused to express his personal view on the issue. Instead, the wealthy equity investor has said he preferred a statewide referendum on same-sex marriage, though any such vote in Illinois would have been non binding. Absent a referendum, he said, as governor he would veto such legislation.

The stakes are particularly high for Republicans next year, having lost the governor’s office to Quinn in 2010 following the scandal that sent Democratic Gov. Rod Blagojevich to federal prison. Brady, the GOP nominee, found his bid to keep the campaign focused on fiscal matters upended in the final weeks before the election amid heavy Democratic criticism of his social conservatism.

That loss allowed Democrats, led by longtime House Speaker Michael Madigan, to redraw state legislative and congressional boundaries without Republican input. In 2012, those new maps produced a super-majority of Democrats in the House and Senate and Democratic pickups in the congressional delegation.

David Yepsen, the director of the Paul Simon Public Policy Institute at Southern Illinois University at Carbondale, said the passage of the legislation could help Republicans in the short term.

“This is actually a good thing for Republicans because it gets this issue off the table. This is a loser for them in Illinois,” Yepsen said. “This discussion and in so many of these social issues, some of the rhetoric in this makes them look intolerant. Now, Republicans can focus on their traditional winning issues, fiscal issues, jobs and the economy.”

But in a general election, the GOP’s positioning on social issues in a deepening Democratic state could be exasperated if state Sen. Jim Oberweis of Sugar Grove seeks the Republican nomination for U.S. Senate and wins the March primary. The outspoken Oberweis led the effort to remove Pat Brady as state GOP chairman over Brady’s support of same-sex marriage.

Three House Republicans voted for the gay marriage bill: Reps. Ed Sullivan of Mundelein, Ron Sandack of Downers Grove and Tom Cross of Oswego. Cross is the former House Republican leader now running for state treasurer. As House GOP leader, Cross would have been unlikely to vote for the measure. As a candidate for treasurer, he faces a GOP primary against DuPage County Auditor Bob Grogan, a conservative. The expected Democratic nominee for treasurer is state Sen. Mike Frerichs of Champaign, who had previously been criticizing Cross's lack of support for the measure in an early campaign skirmish.

“In my opinion, More Republicans need to think like these three (GOP) representatives,” said the former state GOP leader Brady, who was recruited by same-sex marriage supporters to lobby on behalf of the bill.

Brady, no relation to Bill Brady, contended “other Republican leaders like (Illinois) Sen. (Mark) Kirk and (re-elected New Jersey Gov.) Chris Christie have gotten on board with marriage equality because the ark of history is heading straight into the direction for marriage equality, probably across the country.”

Christie, in winning re-election Tuesday by a large margin in a Democratic state, had vetoed a same-sex marriage bill as governor. But recently he canceled the state’s appeal of a judge’s decision granting marriage rights to same-sex couples.

Exit polling conducted Tuesday by television and cable news outlets showed only 6 percent of New Jersey voters cited same-sex marriage as the most important issue facing the state, which is more urban and less diverse than Illinois. Among the overall voter sample, 60 percent of New Jersey voters favored same-sex marriage with proponents split equally between Christie and his Democratic opponent.

But to win a general election, a candidate first has to win a primary, and Illinois primary voters tend to be older and more conservative, while surveys have shown supporters of same-sex marriage tend to be younger, more liberal and less religious in their beliefs.

“The support for marriage equality among (people age) 35 and under, even 50 and under, is at tremendously high levels and these are the people that are going to keep voting from election to election,” said Bernard Cherkasov, the chief executive officer of Equality Illinois, a major advocacy group in support of same-sex marriage.

Last year, when Illinois Republicans helped select former Massachusetts Gov. Mitt Romney as the GOP’s presidential nominee, fully 63 percent of the state’s Republican primary voters were age 50 and older with a like percentage describing themselves as conservatives. More than half, 56 percent, said they considered it at least somewhat important that a candidate shared their religious beliefs.

The same-sex marriage issue may come up in the GOP primary amid questions from social conservatives about Rauner, who has said he supports a woman’s right to have an abortion early in pregnancy.

On the Democratic side, passage of the legislation is a major victory for Quinn, who as governor has signed into law several progressive bills but has been looking for a significant win heading into the election year.

“Sure it’s a win. He hasn’t had many. He worked it. He’ll have a big signing ceremony,” Yepsen said of Quinn. But noting the major fiscal issues still confronting the state, including its massive public employee pension debt, Yepsen said: “He needs to score some points.”